Stars

Very Massive Stars Expel More Matter Than Previously Thought

By Andy Tomaswick - June 16, 2025

Very massive stars (VMSs), which typically has masses about 100 times that of our own Sun, are critical components in our understanding of the formation of important astronomical structures like black holes and supernovae. However, there are some observed characteristics of VMSs that don’t fit the expected behavior based on the best models we have of them. In particular, they hover around a relatively limited band of temperatures, which are hard to replicate with typical stellar evolution models. A new paper from Kendall Shepherd and their co-authors at the Institute for Advanced Study (SISSA) in Italy describes a series of new models based on updated solar winds that better fit the observations of VMSs in their natural environment, and might aid in our understanding of the development of some of the most fascinating objects in the Universe.

The Galactic Center Struggles to Form Massive Stars

By Evan Gough - June 11, 2025

Gas clouds in the Milky Way's Galactic Center contain copious amounts of star-forming gas. But for some reason, few massive stars form there, even though similar gas clouds elsewhere in the galaxy easily form massive stars. The clouds also form fewer stars overall. Are they a new type of molecular cloud?

Strange Object is Releasing Regular Blasts of Both X-Rays and Radio Waves

By Carolyn Collins Petersen - May 29, 2025

Just when astronomers think they're starting to understand stellar activity, something strange grabs their attention. That's the case with a newly discovered stellar object called ASKAP J1832-0911. It lies about 15,000 light-years from Earth and belongs to a class of stellar objects called "long-period radio transients." That means it emits radio waves that vary in their intensity on a schedule of only 44 minutes per cycle. It does the same thing in X-ray intensities, which is the first time anybody's seen such a thing coupled with long-period radio transits.

The Search is on for Betel-Buddy

By Mark Thompson - May 29, 2025

Betelgeuse is dying—but not quietly. This colossal red supergiant, already famous for its brightness fluctuations, has now revealed a strange long-term rhythm: a secondary pulse every 2,100 days. One tantalising theory suggests a hidden companion—possibly a second star orbiting Betelgeuse at roughly the distance between Saturn and the Sun, circling every six years. Astronomers recently pointed the Hubble Space Telescope at the giant in search of this elusive "Betel-Buddy" but failed to find it constraining its size and orbit.

One Star Once Orbited Inside the Other in this Bizarre Binary System.

By Mark Thompson - May 27, 2025

Astronomers have spotted a pulsar in a binary system, taking about 3.6 hours for the stars to orbit one another. Their orbit is so close that, from our vantage point, the pulsar's radio signals vanish for roughly one-sixth of each cycle—blocked by the companion's interference. Researchers think that the more massive star died first, exploding as a supernova and collapsing into a neutron star, passing within the atmosphere of the other. It took about 1,000 years to blow away the envelope of material.

Astronomers Identified the Lost Star of 1408…Or Have They?

By Mark Thompson - May 27, 2025

Over the past 90 years, astronomers have successfully matched several Chinese historical records of "guest stars" with known supernovae. However, identifying historical novae (smaller stellar explosions) has proven to be far more challenging, with many proposed candidates later turning out to be comets or meteors instead. One particularly debated case involves a guest star recorded in 1408 CE by Chinese astronomers. A team of astronomers now think they may have finally been able to identify the event, a rare nova that could potentially solve this centuries old astronomical mystery.

Astronomers Can Classify Satellites By Watching How They Block Stars

By Evan Gough - May 16, 2025

The satellite population in Low-Earth Orbit (LEO) is not an open book. While data on many satellites is public, others are shrouded in secrecy, and information is incomplete for others. New research shows how observers can determine satellite shapes by watching them occult background stars.

There's No Simple Origin Story for Long Gamma Ray Bursts

By Brian Koberlein - May 14, 2025

Gamma-ray bursts (GRBs) are the most powerful phenomena in the Universe. First detected during the Cold War, these events beam a tremendous amount of high-energy light our way in a short period of time. They come in two types: short GRBs that last for less than two seconds and long GRBs that last for minutes. Both types have mysterious origins. Short GRBs could be caused by the collisions of neutron stars or perhaps the powerful flares of a magnetar. Observations of long GRBs suggest they are caused by a powerful supernova called a hypernova, where a massive star collapses to become a black hole. But a new study suggests that the origins of long GRBs are more diverse.

Tracking Down "Annihilation Photons" Could Lead To Unique Binary Systems

By Andy Tomaswick - May 13, 2025

Tracking the sources of photons is a hobby of many astrophysicists. Some types of photons are tied so closely to particular phenomena that tracking their sources would help answer some larger questions in astrophysics itself. Photons on the "511 keV line" are one such type of photon, and they have been overrepresented near the galactic core, with no known source being prolific enough to create them. A new paper from Zachary Metzler and Zorawar Wadiasingh of the University of Maryland and NASA's Goddard Space Flight Center suggests one potential source - millisecond pulsar (MSP) binaries.

How Do the Most Massive Stars Get So Big?

By Evan Gough - May 07, 2025

The most massive stars in the Milky Way contain one hundred times more mass than the Sun, even more in some cases. These O-type stars are extremely hot, luminous, and blue, and often die in supernova explosions. Astrophysicists want to know how they get so big, and a simple household chemical might hold the answer.

Free Floating Binary Planets Can't Last Long

By Evan Gough - May 06, 2025

The JWST continues to live up to its promise by revealing things hidden from other telescopes. One of its lesser-known observations concerns Free-Floating Planets (FFP). FFPs have no gravitational tether to any star and are difficult to detect because they emit so little light. When the JWST detected 42 of a particular type of FFP in the Orion Nebula Cluster, it gave astronomers an opportunity to study them more closely.

Explore These Fascinating 3D Models of Supernovae Remnants and Stars

By Evan Gough - May 02, 2025

NASA's Chandra X-ray Observatory has released new 3D models of space objects that many Universe Today readers will be familiar with. The list includes the supernova remnants Cassiopeia A, G292.0+1.8, the Cygnus Loop, and the young T Tauri star BP Tau. The models are based on observations from space telescopes, theoretical models, and computational algorithms.

New Research Traces Heavy Elements to Collapsing Stars

By Matthew Williams - May 01, 2025

A team of researchers led by the Los Alamos National Laboratory examined the possibility that the jets coming from collapsing stars could be responsible for creating the heaviest elements in the Universe.

This Odd Group of Stars is Eager to Leave its Birthplace

By Evan Gough - April 29, 2025

Stars don't exist in isolation. They have siblings and exist in clusters, associations, and groups. The ESA's Gaia mission found an unusual group of stars rapidly leaving its birthplace behind and dispersing into the wider galaxy. While that's not necessarily unusual behaviour, it is for such a large group. Could supernovae explosions be responsible?

A Dark Nebula with a Starry Background

By Carolyn Collins Petersen - April 28, 2025

Star birth is a process hidden inside dense crèches of gas and dust. Yet, if you know what to look for, you can see the products of this essential cosmic process across the sky. The Circinus West molecular cloud is a starbirth crèche some 2,500 light-years away. It boasts everything from dark nebulae to protostellar objects and newborn stars to the faint ghosts of stars that have already died.

A Planet Found in Perpendicular Orbit Around Two Stars

By Mark Thompson - April 22, 2025

The planets in our Solar System orbit the Sun along a plane extending from the solar equator. That's typically the case for exoplanets too but just recently, a team of astronomers have found a system where a planet is in a perpendicular orbit around a binary pair! The brown dwarf system with its strange planetary companion is likely the result of three-body interactions between the stars and planet, tweaking it into the crazy orbital configuration we see today.

The Evidence for Ancient Supernovae Is Buried Underground

By Paul Sutter - April 19, 2025

The solar system is currently embedded deep within the Local Bubble, a region of relatively low density stretching for a thousand light-years across. It was carved millions of years ago by a chain of supernova explosions. And the evidence for it is right under our feet.

The Most Metal Poor Stars are Living Fossils from the Beginning of the Universe

By Brian Koberlein - April 15, 2025

Our Sun, like all stars, is made mostly of hydrogen and helium. They are by far the most abundant elements, formed in the early moments of the Universe. But our star is also rich in other elements astronomers call "metals." Carbon, nitrogen, iron, gold, and more. These elements were created through astrophysical processes, such as supernovae and neutron star collisions. The dust of long-dead stars that gathered together into molecular clouds and formed new, younger stars such as the Sun. Stars rich in metals. But there are still stars out there that are not metal rich. These extremely metal-poor stars, or EMPs, hold clues to the origin of stars in the cosmos.

There's a Type 1a Supernova in the Making, Just 150 Light-Years Away

By Mark Thompson - April 07, 2025

Astronomers have discovered a remarkable star system just 150 light-years from Earth that's destined for a spectacular cosmic display. The system contains a white dwarf star drawing material from its companion star, with the pair orbiting at just 1/60th of the Earth-Sun distance. With their combined mass reaching 1.56 times that of our Sun, these stars are gradually spiralling toward each other, setting the stage for a spectacular explosion. Fortunately, scientists estimate this cataclysmic event won't occur for roughly 23 billion years, long after our own Sun will have reached the end of its life cycle.

Researchers are Continuing to Scale Up Lightsails That Could Explore the Cosmos

By Mark Thompson - March 26, 2025

It's been almost 10 years since Breakthrough Starshot began funding research into interstellar missions. Back then, state of the art meant a tiny lightsail just 0.25mm across, skip forward to today and, following their funded research, a new prototype has been revealed measuring 60mm x 60mm and just 200 nanometres thick! We are not quite able to use it to hop to Proxima Centauri but the technology keeps advancing until that day arrives.

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